Defining The Current Status; Flow Control Parameters; Table 3-2 Read-Only Parameters Defining The Current Status; Table 3-3 Read-Write Flow Control Parameters Values And Descriptions - Sun Microsystems GigabitEthernet/S 2.0 Installation And User Manual

Defining the Current Status

The read-only parameters described in
interface. These parameters define the current status.
TABLE 3-2
Parameter
link_status
link_speed
link_mode

Flow Control Parameters

The GEM ASIC is capable of sourcing (transmitting) and terminating (receiving)
pause frames conforming to IEEE 802.3x Frame Based Link Level Flow Control
Protocol. In response to received flow control frames, the GEM can slow down its
transmit rate. On the other hand, GEM is capable of sourcing flow control frames,
requesting the link partner to slow down, provided that the link partner supports
this feature. By default, GEM advertises Receive PAUSE capability, during auto
negotiation.
TABLE 3-3
Parameter
adv_pauseTX
adv_pauseRX
For normal operations, GEM doesn't need to source flow control frames. However, if
GEM is operating on a slow bus (for instance, 33 MHz PCI bus slot), and there is a
lot of frame reception activity, there could be a performance degradation due to
Receive FIFO overflow. If the link partner is capable of terminating PAUSE flow
control frames, the performance of GEM could be improved by enabling
adv_pauseTX and restarting auto-negotiation.
16 Sun GigabitEthernet/S 2.0 Adapter Installation and User's Guide • September 1998
Read-Only Parameters Defining the Current Status
Values
0
1
0
1
0
1
Read-Write Flow Control Parameters Values and Descriptions
Values Description
(on/off)
0, 1 Transmit PAUSE Capable (default: not capable)
0, 1 Receive Pause Capable (default: capable)
explain the operational mode of the
TABLE 3-2
Description
Current link status
= Link down
= Link up
Valid only if the link is up
= Link is not up
= 1000 Mbps
Valid only if the link is up
= Half duplex
= Full duplex